Electric-current indicator



(No Model.) 2 Sheets-Sheet 1.

R H MATHBR ELECTRIC CURRENT INDICATOR.

Patented Oct. 26, 1886.

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ELECTRIC CURRENT INDICATOR.

No. 351,388. E Patented Oct. 26, 1886.

UNITED VSTATES PATENT OFFICE.

RICHARD H. MATHER, OF VINDSOR, CONNECTICUT.

ELECTRIC-@CURRENT INDICATOR.

SPECIFICATION forming part of Letters Patent No. 351,388, dated @ct-citer 26, 1886,

Application tiled .lvl'areh l5, 1886. Serial No. 195,197. (No model.)

To @ZZ whom zit may concern:

Beit known that l, Rrcrrann H. lifIATHEn, a citizen of the United States, residing at Windsor, in the county of Hartford and State of Connecticut, have invented certain new and useful. Improvements in Electric Indicators, of

which the following is a specication, refer-y ence being had to the accompanying draw' ings.

My invention relates to visual and audible signals indicating changes in current or electro-motive force in electric circuits.

The object of my invention is to provide a better indicator of such chan ges than has here* tofore been used or known. To accomplish thislobject I ina-ke use ot' a compound electroinagnet whose armature carries ahannner and pointer, in combination with other electrical and mechanical devices which are illustrated iu the accompanying drawings.

In the drawings, Figure l is a front View of my improved'indicator and a containingboX, the latter being thrown open.. Fig. 2 is a side view of the same, the near side of the box being removed. Fig. 3 is a longitudinal section of the electro-magnet which is shown in Figs. l and 2.

This magnet comprises a spool or bobbin of soft iron, A, upon which are wound in the usual manner two separate helices, B and C, of insulated copper wire. The ends of the spool A are enlarged and extended in polepieees D D7 which are concave toward each other on the front side of the magnet. Spool A is further provided with a central annular projection or ring, E, upon which the armay ture F is mounted by a central pivot orscrew,

G. Armature F is a plate, which is perforated in the .middle for screw G, and is rounded at the ends upon the same curve as the concave of surfaces which are presented thereto by pole-pieces D D.

The helices B andCare respectively formed of coarse and line' wi re, and are wound to that degree of electromagnetic efficiency which is hereinafter stated. This magnet is secured by suitable screws, H, to the back Iof the containing-box K. Said magnet is provided with a spring, L, which tends to turn. armati'ire F upon pivot G away from pole-pieces D D with a degree of force which is hereinafter specified.

M is a brass pointer, which is rigidly mounted upon armature F, and passes movabl y through a slot, N, in the top O of box K. The exposed end of pointer M is free to traverse the scale or graduated plate l) whenever motion is imparted to armature F. Plate?, which is attached to the upward-projecting back I of box K, is graduated :in the manner hereinafter described. y

Q is a brass ball or hammer, being an. enlargement of pointer M at a convenient distance from the free end of the latter. On op posite sides of pointer M, and within. reach of hammer Q, are gongs R and S7 which yield noticeably dissimilar tones when struck. This dissimilarity may conveniently be produced byadifferenee in the pitch ofthe musical tones omitted, S being .pitched high and R being pitched low.

T and U are resistanceeoils.

V and IV are binding-posts, being the terminals of the indicator.

X X is the electric circuit in which the indicator is inserted. coils T and U are electrically connected in series between said terminals by the coarse wires l, 2, '3, and 4:. Gong R is connected with wire 2 between helix D and coil U by wire 5, while gong S is connected with wire4or post W' by wire 8. Helix C is .connected 'with pointer M by wire 7 and with wire 3 between coils T and U by wire 6. The normal current of the circuit X X, in which the indicator is placed, is indicated. by the central figures upon scale-plate I. Thus the normal current indicated in Fig. l is ten ampres.

The eleetro-magneticy efficiency of helix B and the traction of spring L are such relatively to each other that whenever the normal current traverses helix B the pointer M is held in equilibrium in the position shown in Fig. l, midway between gongs It and S. The gures 9 and ll upon scale-plate P indicate those deflections of pointer M which con respond, respectively, with a decrease andincrease ol' current by a single ampere above or below the normal current just mentioned.

The gongs R and S are placed upon opposite Sides of the normal position of hammer Q at such equal distances therefrom that said hammer will touch one or the other of said gouge I-Ielix B and resistance.

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whenever the pointer M has reached aI predetermined amplitude of dcileciion. Thus in Fig. l the hammer Q encounters gong R whenever pointer M is deflected half-way from 10 toward 9 of the scale-plate l), and encounters gong S whenever pointer M is deflected haltway from l() toward li of said plate. Yet the gongs R and S may, ii desired, be nearer or i'arther apart, so that hammer Q can encounter said gongs only when said pointer has reached some other desired or predetermined dellection from its normal position; or said gongs may, if desired, be placed at unequal distances from the normal position ot said pointer. The electro-magnetic el'lieiency ot' helices B and C is such that when said helices are enmgized in one and the same direction by an aggregate current of nine and one-halll ampres the niagnetic attraction exerted upon armature F distinctly exceeds the opposing power oi" spring L, and when said helices are energized in opposite directions by an aggregate current of tcn and one-half ampres the magnetic attraction exerted upon armature F less than the opposing power of said spring. The resistance of coils T and U is such that in the normal operationoi" the indicator, as hereinafter described, the current supplied will be distributed to helices i2 and C in that manner which is inxolved in the foregoing statement of the relative efficiency of said helices.

The remaining features oi' construction of this instrument will sui'iiciently appear from said drawings and from the inode of operation, as hereinafter described.

Such being the construction ol' my improved indicator, the inode ol' its operation is as follows: lVhen no current passes through the indicator, the hammer t), is held in contact with gong 'it by the torce of spring L. XVhen a normal curreiit--ten ampres in the present instanee--is present in circuit X X, that cur rent passes from bindingpost Y successively through wire i, helix B, wire i2, resistance` coil U, 'wire 3, resistaneeecoil T, and wire 4 to binding post lV, and the pointer ill is heid in the position shown in Fig. l. It' the current rises above or falls below ten ampres, the change is indicated to the eye of the observer by a corresponding dcliection of pointer M to the right or lett before the index plate lh Whenever the current falls to nine and one-half ampres, or lower, the hammer Q is brought to contact with gong R by the preponderating force of spring L. In that case an electric circuit is closed at the point of contact, so that the current is divided at a point between helix B and resistance-coil U, and passes from terminal toterininal of the indicator in the following manner: From terminal Y said current passes undivided through wire l, helix B, and wire 2 as lar as thejunction. et' wires 2 and 5. There the current dirides, and while the principal part thereof goes on by the way of wire 2 and passes successively through resistance-coil lfi,wirc 3, re-

sistance-coil T, and wire it to terminal lV, the residue of the same passes from the junction of wires 2 and 5 successively through wire 5, gong It, hammer Q, pointer M, wire T, helix U, wire t, resistance-coil T, and wire llto terminal \V. The heiiees B and C ai'e thus en ergized in one and the same direction, and their combined electromagnetic el't'ect is such as to cause the hammer t) to be withdrawn fronrthe gong lll, notwithstanding the opposing force ol spring` L; but when the contact between hammer Q and gong R is broken in the man neri ust stated, hammer Q, being again actuated only by spring L and bythe inagnetic attract-ion vdue to the electro-imignetic eiliciency oi'lielix B, is forthwith ln'onghtback with a blow against gong t, and by this action, indefinitely repeated, gong It is rung until the current rises above nine and one-halt' ampres, or falls so low that the entire strength ot' said magnet is insufficient to break thc contact between hammer Q and gong t against the opposing force of spring L. On the other hand, whenever the current rises to ten and onehalfampres, or 1n ore,tlie hammer Q is brought to Contact with gong` S by the preponiflerating force of said magnet. In that case an electric circuit is closed at the point of contact between Qand S, softhat the currentl is divided at a point between said resistance-coils, and passes f rom terminal to terminal of the indicator in the i'ollowing manner: From terminal V said cnr rent passes undivided through wire l, helix B, wire 2, resistance-coil UI- and wire 3 as l'ar as the junction ot' wires 3 and t. There the current divides, and whilethe principal part thereof proceeds by wire 3 and passes through re` sistance-coil T and wire et to terminal XV, the residue of the same passes from the junction ol wires 3 and G successively through wire t3, helix C, wire T, poiiitei M, hammer Q, gong S, and wire S to terminal V. The helices B and C are thus energized in opposite directions7 and'their differential. electromagnetic -cftcct is such as to cause hammer Q to be withdrawn from gong S by thc preponderating encrgyof spring L. When the contact between hammer Q and gong S is broken, as described, hammer Q, being again actuated only byspring L and bythe magnetic attraction due to the electro-magnetic elliciency of helix i, is forthwith brought bacl; with. a blow against gong S, and by this` action, indeiinitcly repeated, gong S is rung until the current falls below ten and one-halt` ampres, or rises so high that the combined force ot' spring L and of the attraction due to helix C are insufficient to breakv the contact between hammer Q and gong S against the opposing l'orce of the attraction which is duc to the electromagnetic efticicncy ci' helix B The foregoing statement of the construction and mode of operation of my improved indicator has particular reference to my .invent-ion when constructed and used as an ammeler. When constructed and used as avoltmeter, my

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circuit above specified, is a shunt-circuit de`V rived therefrom.

I claim as my invention and desire to secure by Letters Patentil. An electro-magnet wound with two independent helices, an armature pivoted between pole-pieces of said electro-magnet, a spring acting upon said armature, and a ham mer which is mounted upon said armature, in combination with. two gongs which are mounted upon opposite sides of said hammer, and with two resistance-coils which are at all times electrically connected in series with one of said helices, while the other of said helices is connected in parallel with one or the other, or neither, of said resistancecoils, according as said hammer is for the time being in contact with one or the other, or neither, of said gongs, substantially as and for the purpose specified.

2. A compound electromagnet, a pivoted armature thereof provided with a spring and armed with a pointer, and an index-plate near said pointer, in Vcombination with two gongs which are mounted within reach of said pointer, and with two resistance-coils which are connected in series with one oi the helices of said electro-magnet, while the other of said helices is connected in parallel with one or other, or neither, of said resistance-coils, according as said pointer iis for the time beingin circuit with one or the other, or neither, of said gongs, substantially as and for the purpose specified.

3. An electromagnet having twoindependent helices, an armature pivoted within the magnetic field of said electro-magnet, a spring acting upon said armature, and a hammer actuated by said armature, in combination with alarm mechanism and with two resistance-coils which are connected in serieswith one of said helices, while the other of said helices is connected in parallel with one or the other of said resistance-coils whenever said hammer is car ried to a predetermined limit in either direction, substantially as and for the purpose specified.

at. An electric indicator consisting of one or more gongs, a hammer for striking the same, and a compound electromagnet having apivoted armature actuating said hammer, in com bination with two resistances which are conncctedin series with one of the helices of said e1ectro-magnet,while the other of said helices is connected in parallel with one or the other of said resistances whenever said armature is moved to a predetermined limit in either direction, substantially as and for the purpose specified.

5. The gongs R and'S, the resistancecoils T and U, and the hammer Q of pointer M, provided with spring L, in combination with armature F of a compound electro-magnet, and with electrical connections l, 2, 3, 4, 5, 6, 7, and S, substantially as and for the purpose speciiied.

6. A compound electro-magnet, an armature thereof, and a spring acting upon said armature, in combination with two resistances provided with suitable contacts and connections, whereby both of said resistances are at all times electrically connected in series with one of the helices of said electro-magnet, while the other of said helices is connected withone or the other, or neither, of said resistances, according as said armature is moved to a predetermined limit in one direction. or in the other direction, or is not moved to that limit, sub stantially as and for the purpose specified.

In witness whereof I have hereunto set my name in the presence of two witnesses.

RICHARD i H. M ATHER.

Witnesses:

XVILLARD EDDY, CHARLES E. BYRNE. 

